Apparatus and method for adaptive ramped control of positive airway pressure (PAP)

ABSTRACT

Methods and/or apparatus automate setting of a pressure ramp to permit pressure to gradually arrive at a treatment pressure such as in the initial or pre-sleep stages of use of a respiratory therapy pressure device for treatment of a respiratory disorder during sleep (e.g., sleep disordered breathing). In an example, apparatus for treating a respiratory disorder may include a breathable gas pressure generating device. The apparatus may include a controller, including a processor(s). The controller may be configured to collect historic sleep onset parameter(s) concerning timing of a patient falling asleep. The apparatus may determine, based on the historic sleep onset parameter(s), a pre-sleep limit. The apparatus may determine a pre-sleep profile of pressure versus time having a duration spanning the pre-sleep limit and having a plurality of ramping sub-therapeutic pressures. The apparatus may control, upon initiation of treatment, setting of the pressure generating device according to the pre-sleep profile.

1 CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Australian ProvisionalPatent Application Number AU 2016903685, filed on Sep. 14, 2016, theentire contents of which is incorporated herein by reference.

2 STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

3 THE NAMES OF PARTIES TO A JOINT RESEARCH DEVELOPMENT

Not Applicable

4 SEQUENCE LISTING

Not Applicable

5 BACKGROUND OF THE INVENTION 5.1 Field of the Invention

The present technology relates to one or more of the detection,diagnosis, treatment, prevention and amelioration of respiratory-relateddisorders. In particular, the present technology relates to medicaldevices or apparatus, and their use.

5.2 Description of the Related Art

5.2.1 Human Respiratory System and its Disorders

The respiratory system of the body facilitates gas exchange. The noseand mouth form the entrance to the airways of a patient.

The airways include a series of branching tubes, which become narrower,shorter and more numerous as they penetrate deeper into the lung. Theprime function of the lung is gas exchange, allowing oxygen to move fromthe air into the venous blood and carbon dioxide to move out. Thetrachea divides into right and left main bronchi, which further divideeventually into terminal bronchioles. The bronchi make up the conductingairways, and do not take part in gas exchange. Further divisions of theairways lead to the respiratory bronchioles, and eventually to thealveoli. The alveolated region of the lung is where the gas exchangetakes place, and is referred to as the respiratory zone. See“Respiratory Physiology”, by John B. West, Lippincott Williams &Wilkins, 9th edition published 2011.

A range of respiratory disorders exist.

Obstructive Sleep Apnea (OSA), a form of Sleep Disordered Breathing(SDB), is characterized by occlusion or obstruction of the upper airpassage during sleep. It results from a combination of an abnormallysmall upper airway and the normal loss of muscle tone in the region ofthe tongue, soft palate and posterior oropharyngeal wall during sleep.The condition causes the affected patient to stop breathing for periodstypically of 30 to 120 second duration, sometimes 200 to 300 times pernight. It often causes excessive daytime somnolence, and it may causecardiovascular disease and brain damage. The syndrome is a commondisorder, particularly in middle aged overweight males, although aperson affected may have no awareness of the problem. See U.S. Pat. No.4,944,310 (Sullivan).

Cheyne-Stokes Respiration (CSR) is a disorder of a patient's respiratorycontroller in which there are rhythmic alternating periods of waxing andwaning ventilation, causing repetitive de-oxygenation and re-oxygenationof the arterial blood. It is possible that CSR is harmful because of therepetitive hypoxia. In some patients CSR is associated with repetitivearousal from sleep, which causes severe sleep disruption, increasedsympathetic activity, and increased afterload. See U.S. Pat. No.6,532,959 (Berthon-Jones).

Obesity Hyperventilation Syndrome (OHS) is defined as the combination ofsevere obesity and awake chronic hypercapnia, in the absence of otherknown causes for hypoventilation. Symptoms include dyspnea, morningheadache and excessive daytime sleepiness.

Chronic Obstructive Pulmonary Disease (COPD) encompasses any of a groupof lower airway diseases that have certain characteristics in common.These include increased resistance to air movement, extended expiratoryphase of respiration, and loss of the normal elasticity of the lung.Examples of COPD are emphysema and chronic bronchitis. COPD is caused bychronic tobacco smoking (primary risk factor), occupational exposures,air pollution and genetic factors. Symptoms include: dyspnea onexertion, chronic cough and sputum production.

Neuromuscular Disease (NMD) is a broad term that encompasses manydiseases and ailments that impair the functioning of the muscles eitherdirectly via intrinsic muscle pathology, or indirectly via nervepathology. Some NMD patients are characterised by progressive muscularimpairment leading to loss of ambulation, being wheelchair-bound,swallowing difficulties, respiratory muscle weakness and, eventually,death from respiratory failure. Neuromuscular disorders can be dividedinto rapidly progressive and slowly progressive: (i) Rapidly progressivedisorders: Characterised by muscle impairment that worsens over monthsand results in death within a few years (e.g. Amyotrophic lateralsclerosis (ALS) and Duchenne muscular dystrophy (DMD) in teenagers);(ii) Variable or slowly progressive disorders: Characterised by muscleimpairment that worsens over years and only mildly reduces lifeexpectancy (e.g. Limb girdle, Facioscapulohumeral and Myotonic musculardystrophy). Symptoms of respiratory failure in NMD include: increasinggeneralised weakness, dysphagia, dyspnea on exertion and at rest,fatigue, sleepiness, morning headache, and difficulties withconcentration and mood changes.

Chest wall disorders are a group of thoracic deformities that result ininefficient coupling between the respiratory muscles and the thoraciccage. The disorders are usually characterised by a restrictive defectand share the potential of long term hypercapnic respiratory failure.Scoliosis and/or kyphoscoliosis may cause severe respiratory failure.Symptoms of respiratory failure include: dyspnea on exertion, peripheraloedema, orthopnea, repeated chest infections, morning headaches,fatigue, poor sleep quality and loss of appetite.

Otherwise healthy individuals may take advantage of systems and devicesto prevent respiratory disorders from arising.

5.2.2 Therapy

Nasal Continuous Positive Airway Pressure (CPAP) therapy has been usedto treat Obstructive Sleep Apnea (OSA). The hypothesis is thatcontinuous positive airway pressure acts as a pneumatic splint and mayprevent upper airway occlusion by pushing the soft palate and tongueforward and away from the posterior oropharyngeal wall.

Non-invasive ventilation (NIV) provides ventilator support to a patientthrough the upper airways to assist the patient in taking a full breathand/or maintain adequate oxygen levels in the body by doing some or allof the work of breathing. The ventilator support is provided via apatient interface. NIV has been used to treat CSR, OHS, COPD, NMD, andChest Wall disorders.

5.2.3 Systems

One known device for providing CPAP therapy (PAP device) is the S9 SleepTherapy System, manufactured by ResMed. Ventilators such as the ResMedStellar™ Series of Adult and Paediatric Ventilators may provide supportfor non-invasive non-dependent ventilation for a range of patients fortreating a number of conditions such as but not limited to CSR, NMD, OHSand COPD.

A system may comprise a PAP Device/ventilator, an air circuit, ahumidifier, a patient interface, and data management.

5.2.4 Patient Interface

A patient interface may be used to interface respiratory equipment toits user, for example by providing a flow of air. The flow of air may beprovided via a mask to the nose and/or mouth, a tube to the mouth or atracheostomy tube to the trachea of the user. Depending upon the therapyto be applied, the patient interface may form a seal, e.g. with a faceregion of the patient, to facilitate the delivery of gas at a pressureat sufficient variance with ambient pressure to effect therapy, e.g. apositive pressure of about 10 cm H₂O. For other forms of therapy, suchas the delivery of oxygen, the patient interface may not include a sealsufficient to facilitate delivery to the airways of a supply of gas at apositive pressure of about 10 cm H₂O.

5.2.5 Respiratory Apparatus (PAP Device/Ventilator)

Examples of respiratory apparatus include ResMed's S9 AutoSet™ PAPdevice and ResMed's Stellar™ 150 ventilator. PAP devices or ventilatorstypically comprise a pressure device, such as a motor-driven blower or acompressed gas reservoir, and are configured to supply a flow of air tothe airway of a patient. In some cases, the flow of air may be suppliedto the airway of the patient at positive pressure. The outlet of the PAPdevice or the ventilator is connected via an air circuit to a patientinterface such as those described above.

6 BRIEF SUMMARY OF THE TECHNOLOGY

The present technology is directed towards providing medical devicesused in the diagnosis, amelioration, treatment, or prevention ofrespiratory disorders having one or more of improved comfort, cost,efficacy, ease of use and manufacturability.

A first aspect of the present technology relates to apparatus used inthe diagnosis, amelioration, treatment or prevention of a respiratorydisorder.

Another aspect of the present technology relates to methods used in thediagnosis, amelioration, treatment or prevention of a respiratorydisorder.

A further aspect of the present technology relates to systems used inthe diagnosis, amelioration, treatment or prevention of a respiratorydisorder.

Some versions of the present technology include methods and/or apparatusfor automated setting of timing of a ramp for pressure to permit thepressure to gradually arrive at a treatment pressure such as in theinitial or pre-sleep stages of use of a respiratory therapy pressuredevice that may be used for treatment of a respiratory disorder duringsleep (e.g., sleep disordered breathing).

Some versions of the present technology include apparatus(es) fortreating a respiratory disorder. The apparatus may include a breathablegas pressure generating device. The apparatus may include a controller,including at least one processor. The controller may be configured tocollect one or more historic sleep onset parameters concerning timing ofa patient falling asleep. The controller may be configured to determine,based on the one or more historic sleep onset parameters, a pre-sleeplimit. The controller may be configured to determine a pre-sleep profileof pressure versus time having a duration spanning the pre-sleep limitand having a plurality of ramping sub-therapeutic pressures. Thecontroller may be configured to control, upon initiation of treatment,setting of the breathable gas pressure generating device according tothe pre-sleep profile of pressure versus time.

The controller may be configured to collect the one or more historicsleep onset parameters by detecting, with one or more sensors, sleeponset of the patient during use of the breathable gas pressuregenerating device. The controller may be configured to collect the oneor more historic sleep onset parameters by determining a length of timefor the sleep onset of the patient. The controller may be configured tocollect the one or more historic sleep onset parameters by receiving asleep onset time at a user input device. The controller may beconfigured to calculate the pre-sleep limit as a function of any one of:a maximum of a plurality of the historic sleep onset parameters; a meanof a plurality of the historic sleep onset parameters; and a percentileof the one or more historic sleep onset parameters.

The controller may be configured to calculate the pre-sleep limit from apercentile of a plurality of the historic sleep onset parameters, andwherein the pre-sleep limit may be calculated as a percentage of thepercentile. The controller may be configured to collect a plurality ofthe historic sleep onset parameters according to a window timeframecomprising a number of treatment sessions. The window timeframe may be arolling window timeframe. The controller may be further configured toset a default pre-sleep limit in an absence of a sufficient collectionof one or more historic sleep onset parameters.

The controller may be configured to control a display to provide aprompt for input, the prompt for input including: one or both of (a) atleast one of the one or more historic sleep onset parameters, and (b) atleast one calculated statistic concerning the one or more historic sleeponset parameters. The controller may be configured to determine thepre-sleep limit based on input received in response to the prompt.

In some versions, the pre-sleep profile may start delivered pressure ata first pressure and may end at a minimum therapeutic pressure. Theminimum therapeutic pressure may be higher than the first pressure.

Some versions of the present technology include a method(s) forcontrolling a pressure treatment for a respiratory disorder. The methodmay include generating a flow of breathable gas at a pressure aboveatmospheric pressure with a pressure generating device. The method mayinclude, such as in one or more controllers: collecting one or morehistoric sleep onset parameters concerning timing of a patient fallingasleep; determining, based on the one or more historic sleep onsetparameters, a pre-sleep limit; determining a pre-sleep profile ofpressure versus time having a duration spanning the pre-sleep limit andhaving a plurality of ramping sub-therapeutic pressures; and/orcontrolling, upon initiation of treatment, setting of the flow ofbreathable gas according to the pre-sleep profile of pressure versustime.

The method may include, such as in the one or more controllers,collecting the one or more historic sleep onset parameters by detecting,with one or more sensors, sleep onset of the patient during use of thebreathable gas pressure generating device; and determining a length oftime for the sleep onset of the patient. The collecting of the one ormore historic sleep onset parameters may include receiving a sleep onsettime at a user input device. The method may include, such as in one ormore controllers, calculating the pre-sleep limit as a function of anyone of: a maximum of a plurality of the historic sleep onset parameters;a mean of a plurality of the historic sleep onset parameters; and apercentile of the one or more historic sleep onset parameters. Themethod may include, such as in one or more controllers, calculating thepre-sleep limit from a percentile of a plurality of the historic sleeponset parameters, wherein the pre-sleep limit is calculated as apercentage of the percentile. The method may include, such as in one ormore controllers, collecting a plurality of the historic sleep onsetparameters according to a window timeframe comprising a number oftreatment sessions. The window timeframe may be a rolling windowtimeframe.

In some versions, the method may include, such as in one or morecontrollers, setting a default pre-sleep limit in an absence of asufficient collection of one or more historic sleep onset parameters.The method may include, such as in the one or more controllers:controlling a display to provide a prompt for input, the prompt forinput including: one or both of (a) at least one of the one or morehistoric sleep onset parameters, and (b) at least one calculatedstatistic concerning the one or more historic sleep onset parameters;and determining the pre-sleep limit based on input received in responseto the prompt. The pre-sleep profile may start delivered pressure at afirst pressure and may end at a minimum therapeutic pressure, theminimum therapeutic pressure being higher than the first pressure.

Of course, portions of the aspects may form sub-aspects of the presenttechnology. Also, various ones of the sub-aspects and/or aspects may becombined in various manners and also constitute additional aspects orsub-aspects of the present technology.

Other features of the technology will be apparent from consideration ofthe information contained in the following detailed description,abstract, drawings and claims.

7 BRIEF DESCRIPTION OF THE DRAWINGS

The present technology is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings, in whichlike reference numerals refer to similar elements including:

7.1 Treatment Systems

FIG. 1A shows a system in accordance with the present technology. Apatient 1000 wearing a patient interface 3000, receives a supply of airat positive pressure from a PAP device 4000. Air from the PAP device ishumidified in a humidifier 5000, and passes along an air circuit 4170 tothe patient 1000.

FIG. 1B shows a PAP device 4000 in use on a patient 1000 with a nasalmask 3000.

FIG. 1C shows a PAP device 4000 in use on a patient 1000 with afull-face mask 3000.

7.2 Respiratory System

FIG. 2A shows an overview of a human respiratory system including thenasal and oral cavities, the larynx, vocal folds, oesophagus, trachea,bronchus, lung, alveolar sacs, heart and diaphragm.

FIG. 2B shows a view of a human upper airway including the nasal cavity,nasal bone, lateral nasal cartilage, greater alar cartilage, nostril,lip superior, lip inferior, larynx, hard palate, soft palate,oropharynx, tongue, epiglottis, vocal folds, oesophagus and trachea.

7.3 Patient Interface

FIG. 3 shows a patient interface 3000 in accordance with one form of thepresent technology.

7.4 PAP Device

FIG. 4A shows a PAP device 4000 in accordance with one form of thepresent technology.

FIG. 4B shows a schematic diagram of the pneumatic circuit of a PAPdevice 4000 in accordance with one form of the present technology. Thedirections of upstream and downstream are indicated.

FIG. 4C shows a schematic diagram of the electrical components of a PAPdevice 4000 in accordance with one aspect of the present technology.

FIG. 4D shows a schematic diagram of the algorithms 4300 implemented ina PAP device 4000 in accordance with an aspect of the presenttechnology. In this figure, arrows with solid lines indicate an actualflow of information, for example via an electronic signal.

FIG. 4E is a flow chart illustrating a method 4500 carried out by thetherapy engine module 4320 of FIG. 4D in accordance with one aspect ofthe present technology.

FIG. 4F is a state diagram illustrating an initial phase of operation ofthe therapy engine module 4320 of FIG. 4D in accordance with an aspectof the present technology.

FIGS. 4G and 4H depict graphs illustrating the initial phase ofoperation of the therapy engine module 4320 of FIG. 4D as described withreference to FIG. 4F.

7.5 Humidifier

FIG. 5 shows a humidifier 5000 in accordance with one aspect of thepresent technology.

7.6 Breathing Waveforms

FIG. 6 shows a model typical breath waveform of a person while sleeping.The horizontal axis is time, and the vertical axis is respiratory flow.While the parameter values may vary, a typical breath may have thefollowing approximate values: tidal volume, Vt, 0.5 L, inhalation time,Ti, 1.6 s, peak inspiratory flow, Qpeak, 0.4 L/s, exhalation time, Te,2.4 s, peak expiratory flow, Qpeak, −0.5 L/s. The total duration of thebreath, Ttot, is about 4 s. The person typically breathes at a rate ofabout 15 breaths per minute (BPM), with Ventilation, Vent, about 7.5L/minute. A typical duty cycle, the ratio of Ti to Ttot is about 40%.

8 DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY

Before the present technology is described in further detail, it is tobe understood that the technology is not limited to the particularexamples described herein, which may vary. It is also to be understoodthat the terminology used in this disclosure is for the purpose ofdescribing only the particular examples discussed herein, and is notintended to be limiting.

8.1 Therapy

In one form, the present technology comprises a method for treating arespiratory disorder comprising the step of applying positive pressureto the entrance of the airways of a patient 1000.

8.2 Treatment Systems

In one form, the present technology comprises apparatus for treating arespiratory disorder. The apparatus may comprise a PAP device 4000 forsupplying pressurised air to the patient 1000 via an air delivery tubeleading to a patient interface 3000.

8.3 Patient Interface 3000

A non-invasive patient interface 3000 in accordance with one aspect ofthe present technology comprises the following functional aspects: aseal-forming structure 3100, a plenum chamber 3200, a positioning andstabilising structure 3300 and a connection port 3600 for connection toair circuit 4170. In some forms a functional aspect may be provided byone or more physical components. In some forms, one physical componentmay provide one or more functional aspects. In use the seal-formingstructure 3100 is arranged to surround an entrance to the airways of thepatient so as to facilitate the supply of air at positive pressure tothe airways.

8.4 PAP Device 4000

It should be understood that the PAP device 4000 is described below asbut one form of a respiratory apparatus. Furthermore, one skilled in theart would understand that aspects of the present technology may beapplicable to other forms of respiratory apparatus such as ventilators.

A PAP device 4000 in accordance with one aspect of the presenttechnology comprises mechanical and pneumatic components 4100,electrical components 4200 and is programmed to execute one or morealgorithms 4300. The PAP device 4000 preferably has an external housing4010, preferably formed in two parts, an upper portion 4012 of theexternal housing 4010, and a lower portion 4014 of the external housing4010. In alternative forms, the external housing 4010 may include one ormore panel(s) 4015. In one form, the PAP device 4000 comprises a chassis4016 that supports one or more internal components of the PAP device4000. In one form a pneumatic block 4020 is supported by, or formed aspart of the chassis 4016. The PAP device 4000 may include a handle 4018.

The pneumatic path of the PAP device 4000 preferably comprises an inletair filter 4112, an inlet muffler 4122, a controllable pressure device4140 capable of supplying air at positive pressure (preferably a blower4142), and an outlet muffler 4124. One or more sensors or transducers4270 are included in the pneumatic path.

The preferred pneumatic block 4020 comprises a portion of the pneumaticpath that is located within the external housing 4010.

The PAP device 4000 preferably has an electrical power supply 4210, oneor more input devices 4220, a central controller 4230, a therapy devicecontroller 4240, a therapy device 4245, one or more protection circuits4250, memory 4260, transducers 4270, data communication interface 4280and one or more output devices 4290. Electrical components 4200 may bemounted on a single Printed Circuit Board Assembly (PCBA) 4202. In analternative form, the PAP device 4000 may include more than one PCBA4202.

8.4.1 PAP Device Mechanical & Pneumatic Components 4100

8.4.1.1 Air Filter(s) 4110

A PAP device in accordance with one form of the present technology mayinclude an air filter 4110, or a plurality of air filters 4110.

In one form, an inlet air filter 4112 is located at the beginning of thepneumatic path upstream of a pressure device 4140.

In one form, an outlet air filter 4114, for example an antibacterialfilter, is located between an outlet of the pneumatic block 4020 and apatient interface 3000.

8.4.1.2 Muffler(s) 4120

In one form of the present technology, an inlet muffler 4122 is locatedin the pneumatic path upstream of a pressure device 4140.

In one form of the present technology, an outlet muffler 4124 is locatedin the pneumatic path between the pressure device 4140 and a patientinterface 3000.

8.4.1.3 Pressure Device 4140

In a preferred form of the present technology, a pressure device 4140for producing a flow of air at positive pressure is a controllableblower 4142. For example the blower may include a brushless DC motor4144 with one or more impellers housed in a volute. The blower may bepreferably capable of delivering a supply of air, for example about 120litres/minute, at a positive pressure in a range from about 4 cm H₂O toabout 20 cm H₂O, or in other forms up to about 30 cm H₂O.

The pressure device 4140 is under the control of the therapy devicecontroller 4240.

8.4.1.4 Transducer(s) 4270

In one form of the present technology, one or more transducers 4270 arelocated upstream of the pressure device 4140. The one or moretransducers 4270 are constructed and arranged to measure properties ofthe air at that point in the pneumatic path.

In one form of the present technology, one or more transducers 4270 arelocated downstream of the pressure device 4140, and upstream of the aircircuit 4170. The one or more transducers 4270 are constructed andarranged to measure properties of the air at that point in the pneumaticpath.

In one form of the present technology, one or more transducers 4270 arelocated proximate to the patient interface 3000.

8.4.1.5 Anti-Spill Back Valve 4160

In one form of the present technology, an anti-spill back valve islocated between the humidifier 5000 and the pneumatic block 4020. Theanti-spill back valve is constructed and arranged to reduce the riskthat water will flow upstream from the humidifier 5000, for example tothe motor 4144.

8.4.1.6 Air Circuit 4170

An air circuit 4170 in accordance with an aspect of the presenttechnology is constructed and arranged to allow a flow of air betweenthe pneumatic block 4020 and the patient interface 3000.

8.4.1.7 Oxygen Delivery 4180

In one form of the present technology, supplemental oxygen 4180 isdelivered to a point in the pneumatic path.

In one form of the present technology, supplemental oxygen 4180 isdelivered upstream of the pneumatic block 4020.

In one form of the present technology, supplemental oxygen 4180 isdelivered to the air circuit 4170.

In one form of the present technology, supplemental oxygen 4180 isdelivered to the patient interface 3000.

8.4.2 PAP Device Electrical Components 4200

8.4.2.1 Power Supply 4210

In one form of the present technology power supply 4210 is internal ofthe external housing 4010 of the PAP device 4000. In another form of thepresent technology, power supply 4210 is external of the externalhousing 4010 of the PAP device 4000.

In one form of the present technology power supply 4210 provideselectrical power to the PAP device 4000 only. In another form of thepresent technology, power supply 4210 provides electrical power to bothPAP device 4000 and humidifier 5000.

8.4.2.2 Input Devices 4220

In one form of the present technology, a PAP device 4000 includes one ormore input devices 4220 in the form of buttons, switches or dials toallow a person to interact with the device. The buttons, switches ordials may be physical devices, or software devices accessible via atouch screen. The buttons, switches or dials may, in one form, bephysically connected to the external housing 4010, or may, in anotherform, be in wireless communication with a receiver that is in electricalconnection to the central controller 4230.

In one form the input device 4220 may be constructed and arranged toallow a person to select a value and/or a menu option.

8.4.2.3 Central Controller 4230

In one form of the present technology, the central controller 4230 is aprocessor suitable to control a PAP device 4000 such as an x86 INTELprocessor.

A processor 4230 suitable to control a PAP device 4000 in accordancewith another form of the present technology includes a processor basedon ARM Cortex-M processor from ARM Holdings. For example, an STM32series microcontroller from ST MICROELECTRONICS may be used.

Another processor 4230 suitable to control a PAP device 4000 inaccordance with a further alternative form of the present technologyincludes a member selected from the family ARM9-based 32-bit RISC CPUs.For example, an STR9 series microcontroller from ST MICROELECTRONICS maybe used.

In certain alternative forms of the present technology, a 16-bit RISCCPU may be used as the processor 4230 for the PAP device 4000. Forexample a processor from the MSP430 family of microcontrollers,manufactured by TEXAS INSTRUMENTS, may be used.

The processor 4230 is configured to receive input signal(s) from one ormore transducers 4270, and one or more input devices 4220.

The processor 4230 is configured to provide output signal(s) to one ormore of an output device 4290, a therapy device controller 4240, a datacommunication interface 4280, a heater 5240 and a humidity controller5250.

In some forms of the present technology, the processor 4230, or multiplesuch processors, is configured to implement the one or moremethodologies described herein such as the one or more algorithms 4300expressed as computer programs stored in a non-transitory computerreadable storage medium, such as memory 4260. In some cases, aspreviously discussed, such processor(s) may be integrated with a PAPdevice 4000. However, in some forms of the present technology theprocessor(s) may be implemented discretely from the pneumatic componentsof the PAP device 4000, such as for purpose of performing any of themethodologies described herein without directly controlling delivery ofa respiratory treatment. For example, such a processor may perform anyof the methodologies described herein for purposes of determiningcontrol settings for a ventilator or other respiratory related events byanalysis of stored data such as from any of the sensors describedherein.

The central controller or processor 4230 of the PAP device 4000 isprogrammed to execute one or more algorithm modules 4300, preferablyincluding a pre-processing module 4310, a therapy engine module 4320, atherapy control module 4330, and a fault condition module 4340.

8.4.2.4 Clock 4232

Preferably PAP device 4000 includes a clock 4232 that is connected toprocessor 4230.

8.4.2.5 Therapy Device Controller 4240

In one form of the present technology, the therapy device controller4240 is configured to control the therapy device 4245 to deliver therapyto a patient 1000.

In one form of the present technology, therapy device controller 4240 isa therapy control module 4330 that forms part of the algorithms 4300executed by the processor 4230.

In one form of the present technology, therapy device controller 4240 isa dedicated motor control integrated circuit. For example, in one form aMC33035 brushless DC motor controller, manufactured by ONSEMI is used.

8.4.2.6 Therapy Device 4245

In one form of the present technology, the therapy device 4245 isconfigured to deliver therapy to a patient 1000 under the control of thetherapy device controller 4240.

Preferably the therapy device 4245 is a pressure device 4140.

8.4.2.7 Protection Circuits 4250

Preferably a PAP device 4000 in accordance with the present technologycomprises one or more protection circuits 4250.

One form of protection circuit 4250 in accordance with the presenttechnology is an electrical protection circuit.

One form of protection circuit 4250 in accordance with the presenttechnology is a temperature or pressure safety circuit.

8.4.2.8 Memory 4260

In accordance with one form of the present technology the PAP device4000 includes memory 4260, preferably non-volatile memory. In someforms, memory 4260 may include battery powered static RAM. In someforms, memory 4260 may include volatile RAM.

Preferably memory 4260 is located on PCBA 4202. Memory 4260 may be inthe form of EEPROM, or NAND flash.

Additionally or alternatively, PAP device 4000 includes a removable formof memory 4260, for example a memory card made in accordance with theSecure Digital (SD) standard.

In one form of the present technology, the memory 4260 acts as anon-transitory computer readable storage medium on which is storedcomputer program instructions expressing the one or more methodologiesdescribed herein, such as the one or more algorithms 4300.

8.4.2.9 Transducers 4270

Transducers may be internal of the device 4000, or external of the PAPdevice 4000. External transducers may be located for example on or formpart of the air delivery circuit 4170, e.g. at the patient interface3000. External transducers may be in the form of non-contact sensorssuch as a Doppler radar movement sensor that transmit or transfer datato the PAP device 4000.

8.4.2.9.1 Flow 4274

A flow transducer 4274 in accordance with the present technology may bebased on a differential pressure transducer, for example, an SDP600Series differential pressure transducer from SENSIRION. The differentialpressure transducer is in fluid communication with the pneumaticcircuit, with one of each of the pressure transducers connected torespective first and second points in a flow restricting element.

In one example, a signal representing total flow Qt from the flowtransducer 4274 is received by the processor 4230.

8.4.2.9.2 Pressure 4272

A pressure transducer 4272 in accordance with the present technology islocated in fluid communication with the pneumatic path. An example of asuitable pressure transducer 4272 is a sensor from the HONEYWELL ASDXseries. An alternative suitable pressure transducer is a sensor from theNPA Series from GENERAL ELECTRIC.

In use, a signal from the pressure transducer 4272 is received by theprocessor 4230. In one form, the signal from the pressure transducer4272 is filtered prior to being received by the processor 4230.

8.4.2.9.3 Motor Speed 4276

In one form of the present technology a motor speed signal 4276 isgenerated. A motor speed signal 4276 is preferably provided by therapydevice controller 4240. Motor speed may, for example, be generated by aspeed sensor, such as a Hall effect sensor.

8.4.2.10 Data Communication Systems 4280

In one preferred form of the present technology, a data communicationinterface 4280 is provided, and is connected to processor 4230. Datacommunication interface 4280 is preferably connectable to remoteexternal communication network 4282. Data communication interface 4280is preferably connectable to local external communication network 4284.Preferably remote external communication network 4282 is connectable toremote external device 4286. Preferably local external communicationnetwork 4284 is connectable to local external device 4288.

In one form, data communication interface 4280 is part of processor4230. In another form, data communication interface 4280 is anintegrated circuit that is separate from processor 4230.

In one form, remote external communication network 4282 is the Internet.The data communication interface 4280 may use wired communication (e.g.via Ethernet, or optical fibre) or a wireless protocol to connect to theInternet.

In one form, local external communication network 4284 utilises one ormore communication standards, such as Bluetooth, or a consumer infraredprotocol.

In one form, remote external device 4286 is one or more computers, forexample a cluster of networked computers. In one form, remote externaldevice 4286 may be virtual computers, rather than physical computers. Ineither case, such remote external device 4286 may be accessible to anappropriately authorised person such as a clinician.

Preferably local external device 4288 is a personal computer, mobilephone, tablet or remote control.

8.4.2.11 Output Devices Including Optional Display, Alarms 4290

An output device 4290 in accordance with the present technology may takethe form of one or more of a visual, audio and haptic unit. A visualdisplay may be a Liquid Crystal Display (LCD) or Light Emitting Diode(LED) display.

8.4.2.11.1 Display Driver 4292

A display driver 4292 receives as an input the characters, symbols, orimages intended for display on the display 4294, and converts them tocommands that cause the display 4294 to display those characters,symbols, or images.

8.4.2.11.2 Display 4294

A display 4294 is configured to visually display characters, symbols, orimages in response to commands received from the display driver 4292.For example, the display 4294 may be an eight-segment display, in whichcase the display driver 4292 converts each character or symbol, such asthe figure “0”, to eight logical signals indicating whether the eightrespective segments are to be activated to display a particularcharacter or symbol.

8.4.3 PAP Device Algorithms 4300

8.4.3.1 Pre-Processing Module 4310

A pre-processing module 4310 in accordance with the present technologyreceives as an input, raw data from a transducer, for example a flow orpressure transducer, and preferably performs one or more process stepsto calculate one or more output values that will be used as an input toanother module, for example a therapy engine module 4320.

In one form of the present technology, the output values include theinterface or mask pressure Pm, the respiratory flow Qr, and the leakflow Ql.

In various forms of the present technology, the pre-processing module4310 comprises one or more of the following algorithms: pressurecompensation 4312, vent flow 4314, leak flow 4316, and respiratory flow4318.

8.4.3.1.1 Pressure Compensation 4312

In one form of the present technology, a pressure compensation algorithm4312 receives as an input a signal indicative of the pressure in thepneumatic path proximal to an outlet of the pneumatic block 4020. Thepressure compensation algorithm 4312 estimates the pressure drop in theair circuit 4170 and provides as an output an estimated pressure, Pm, inthe patient interface 3000.

8.4.3.1.2 Vent Flow 4314

In one form of the present technology, a vent flow calculation algorithm4314 receives as an input an estimated pressure, Pm, in the patientinterface 3000 and estimates a vent flow of air, Qv, from a vent 3400 ina patient interface 3000.

8.4.3.1.3 Leak Flow 4316

In one form of the present technology, a leak flow algorithm 4316receives as an input a total flow, Qt, and a vent flow Qv, and providesas an output a leak flow Ql by calculating an average of Qt−Qv over aperiod sufficiently long to include several breathing cycles, e.g. about10 seconds.

In one form, the leak flow algorithm 4316 receives as an input a totalflow, Qt, a vent flow Qv, and an estimated pressure, Pm, in the patientinterface 3000, and provides as an output a leak flow Ql by calculatinga leak conductance, and determining a leak flow Ql to be a function ofleak conductance and mask pressure Pm. Preferably leak conductance iscalculated as the quotient of low pass filtered non-vent flow Qt−Qv, andlow pass filtered square root of mask pressure Pm, where the low passfilter time constant has a value sufficiently long to include severalbreathing cycles, e.g. about 10 second.

8.4.3.1.4 Respiratory Flow 4318

In one form of the present technology, a respiratory flow algorithm 4318receives as an input a total flow, Qt, a vent flow, Qv, and a leak flow,Ql, and estimates a respiratory flow of air, Qr, to the patient, bysubtracting the vent flow Qv and the leak flow Ql from the total flowQt.

8.4.3.2 Therapy Engine Module 4320

In one form of the present technology, a therapy engine module 4320receives as inputs one or more of a pressure, Pm, in a patient interface3000, and a respiratory flow of air to a patient, Qr, and provides as anoutput one or more therapy parameters.

In various forms, the therapy engine module 4320 comprises one or moreof the following algorithms: phase determination 4321, waveformdetermination 4322, ventilation determination 4323, inspiratory flowlimitation determination 4324, apnea/hypopnea determination 4325, snoredetermination 4326, airway patency determination 4327, and therapyparameter determination 4328.

8.4.3.2.1 Phase Determination 4321

In one form of the present technology, a phase determination algorithm4321 receives as an input a signal indicative of respiratory flow, Qr,and provides as an output a phase of a breathing cycle of a patient1000.

In one form, the phase output is a discrete variable with values ofeither inhalation or exhalation. In one implementation of this form, thephase output is determined to have a discrete value of inhalation when arespiratory flow Qr has a positive value that exceeds a positivethreshold, and the phase is determined to have a discrete value ofexhalation when a respiratory flow Qr has a value that is more negativethan a negative threshold.

In one form, the phase output is a discrete variable with values of oneof inhalation, mid-inspiratory pause, and exhalation.

In one form, the phase output is a continuous variable, for examplevarying from 0 to 1, or 0 to 2π radians.

8.4.3.2.2 Waveform Determination 4322

In one form of the present technology, a control module 4330 controls atherapy device 4245 to provide an approximately constant positive airwaypressure throughout a respiratory cycle of a patient.

In one form of the present technology, a control module 4330 controls atherapy device 4245 to provide positive airway pressure according to apredetermined waveform of pressure vs phase. In one form, the waveformis maintained at an approximately constant level for all values ofphase. In one form, the waveform is a square wave, having a higher valuefor some values of phase, and a lower level for other values of phase.

In one form of the present technology a waveform determination algorithm4322 receives as an input a value indicative of current patientventilation, Vent, and provides as an output a waveform of pressure vs.phase.

8.4.3.2.3 Ventilation Determination 4323

In one form of the present technology, a ventilation determinationalgorithm 4323 receives an input a respiratory flow Qr, and determines ameasure indicative of patient ventilation, Vent.

In one form ventilation determination algorithm 4323 determines acurrent value of patient ventilation, Vent, as half the low-passfiltered absolute value of respiratory flow, Qr.

8.4.3.2.4 Determination of Inspiratory Flow Limitation 4324

In one form of the present technology, a processor executes one or morealgorithms 4324 for the detection of inspiratory flow limitation.

In one form the algorithm 4324 receives as an input a respiratory flowsignal Qr and provides as an output a metric of the extent to which theinspiratory portion of the breath exhibits inspiratory flow limitation.

In one form of the present technology, the inspiratory portion of eachbreath is identified by a zero-crossing detector. A number of evenlyspaced points (for example, sixty-five), representing points in time,are interpolated by an interpolator along the inspiratory flow-timecurve for each breath. The curve described by the points is then scaledby a scaler to have unity length (duration/period) and unity area toremove the effects of changing respiratory rate and depth. The scaledbreaths are then compared in a comparator with a pre-stored templaterepresenting a normal unobstructed breath, similar to the inspiratoryportion of the breath shown in FIG. 6a . Breaths deviating by more thana specified threshold (typically 1 scaled unit) at any time during theinspiration from this template, such as those due to coughs, sighs,swallows and hiccups, as determined by a test element, are rejected. Fornon-rejected data, a moving average of the first such scaled point iscalculated by processor 4230 for the preceding several inspiratoryevents. This is repeated over the same inspiratory events for the secondsuch point, and so on. Thus, for example, sixty five scaled data pointsare generated by processor 4230, and represent a moving average of thepreceding several inspiratory events, e.g. three events. The movingaverage of continuously updated values of the (e.g. sixty five) pointsare hereinafter called the “scaled flow”, designated as Qs(t).Alternatively, a single inspiratory event can be utilised rather than amoving average.

From the scaled flow, two shape factors relating to the determination ofpartial obstruction may be calculated.

Shape factor 1 is the ratio of the mean of the middle (e.g. thirty-two)scaled flow points to the mean overall (e.g. sixty-five) scaled flowpoints. Where this ratio is in excess of unity, the breath will be takento be normal. Where the ratio is unity or less, the breath will be takento be obstructed. A ratio of about 1.17 is taken as a threshold betweenpartially obstructed and unobstructed breathing, and equates to a degreeof obstruction that would permit maintenance of adequate oxygenation ina typical user.

Shape factor 2 is calculated as the RMS deviation from unit scaled flow,taken over the middle (e.g. thirty two) points. An RMS deviation ofabout 0.2 units is taken to be normal. An RMS deviation of zero is takento be a totally flow-limited breath. The closer the RMS deviation tozero, the breath will be taken to be more flow limited.

Shape factors 1 and 2 may be used as alternatives, or in combination. Inother forms of the present technology, the number of sampled points,breaths and middle points may differ from those described above.Furthermore, the threshold values can other than those described.

8.4.3.2.5 Determination of Apneas and Hypopneas 4325

In one form of the present technology, a processor 4230 executes one ormore algorithms 4325 for the determination of the presence of apneasand/or hypopneas.

Preferably the one or more algorithms 4325 receive as an input arespiratory flow signal Qr and provide as an output a flag thatindicates that an apnea or a hypopnea has been detected.

In one form, an apnea will be said to have been detected when a functionof respiratory flow Qr falls below a flow threshold for a predeterminedperiod of time. The function may determine a peak flow, a relativelyshort-term mean flow, or a flow intermediate of relatively short-termmean and peak flow, for example an RMS flow. The flow threshold may be arelatively long-term measure of flow.

In one form, a hypopnea will be said to have been detected when afunction of respiratory flow Qr falls below a second flow threshold fora predetermined period of time. The function may determine a peak flow,a relatively short-term mean flow, or a flow intermediate of relativelyshort-term mean and peak flow, for example an RMS flow. The second flowthreshold may be a relatively long-term measure of flow. The second flowthreshold is greater than the flow threshold used to detect apneas.

8.4.3.2.6 Determination of Snore 4326

In one form of the present technology, a processor 4230 executes one ormore snore algorithms 4326 for the detection of snore.

In one form the snore algorithm 4326 receives as an input a respiratoryflow signal Qr and provides as an output a metric of the extent to whichsnoring is present.

Preferably the algorithm 4326 comprises the step of determining theintensity of the flow signal in the range of 30-300 Hz. Furtherpreferably, algorithm 4326 comprises a step of filtering the respiratoryflow signal Qr to reduce background noise, e.g. the sound of airflow inthe system from the blower.

8.4.3.2.7 Determination of Airway Patency 4327

In one form of the present technology, a processor 4230 executes one ormore algorithms 4327 for the determination of airway patency.

In one form, airway patency algorithm 4327 receives as an input arespiratory flow signal Qr, and determines the power of the signal inthe frequency range of about 0.75 Hz and about 3 Hz. The presence of apeak in this frequency range is taken to indicate an open airway. Theabsence of a peak is taken to be an indication of a closed airway.

In one form, the frequency range within which the peak is sought is thefrequency of a small forced oscillation in the treatment pressure Pt. Inone implementation, the forced oscillation is of frequency 2 Hz withamplitude about 1 cm H₂O.

In one form, airway patency algorithm 4327 receives as an input arespiratory flow signal Qr, and determines the presence or absence of acardiogenic signal. The absence of a cardiogenic signal is taken to bean indication of a closed airway.

8.4.3.2.8 Determination of Therapy Parameters 4328

In one form of the present technology, processor 4230 executes one ormore algorithms 4328 for the determination of one or more therapyparameters using the values returned by one or more of the otheralgorithms in the therapy engine module 4320.

In one form of the present technology, the therapy parameter is aninstantaneous treatment pressure Pt. In one implementation of this form,the treatment pressure Pt is given byPt=AP(Φ)+P ₀  (1)

where:

-   -   A is the pressure support,    -   P(Φ) is the waveform value (in the range 0 to 1) at the current        value Φ of phase, and    -   P₀ is a base pressure.

Treatment pressure Pt determined according to equation (1) may bedefined as “therapeutic pressure”. Various therapy modes may be defineddepending on the values of the parameters A and P₀. In someimplementations of this form of the present technology, the pressuresupport A is identically zero, so the treatment pressure Pt isidentically equal to the base pressure P₀ throughout the respiratorycycle. Such implementations are generally grouped under the heading ofCPAP therapy.

The base pressure P₀ may be a constant value that is prescribed and/ormanually entered to the PAP device 4000. This alternative is sometimesreferred to as constant CPAP therapy. Alternatively, the base pressureP₀ may be continuously computed as a function of indices or measures ofone or more of sleep disordered breathing events such as flowlimitation, apnea, hypopnea, patency, and snore returned by therespective algorithms in the therapy engine module 4320. Thisalternative is sometimes referred to as APAP therapy.

FIG. 4e is a flow chart illustrating a method 4500 carried out by theprocessor 4230 to continuously compute the base pressure P₀ as part ofan APAP therapy implementation of the algorithm 4328. In such animplementation, by equation (1) the treatment pressure Pt is identicallyequal to the base pressure P₀.

The method 4500 starts at step 4520, at which the processor 4230compares the measure of the presence of apnea/hypopnea with a firstthreshold, and determines whether the measure of the presence ofapnea/hypopnea has exceeded the first threshold for a predeterminedperiod of time, indicating an apnea/hypopnea is occurring. If so, themethod 4500 proceeds to step 4540; otherwise, the method 4500 proceedsto step 4530. At step 4540, the processor 4230 compares the measure ofairway patency with a second threshold. If the measure of airway patencyexceeds the second threshold, indicating the airway is patent, thedetected apnea/hypopnea is deemed central, and the method 4500 proceedsto step 4560; otherwise, the apnea/hypopnea is deemed obstructive, andthe method 4500 proceeds to step 4550.

At step 4530, the processor 4230 compares the measure of flow limitationwith a third threshold. If the measure of flow limitation exceeds thethird threshold, indicating inspiratory flow is limited, the method 4500proceeds to step 4550; otherwise, the method 4500 proceeds to step 4560.

At step 4550, the processor 4230 increases the base pressure P₀ by apredetermined pressure increment ΔP, such that the resulting treatmentpressure Pt is no greater than an upper APAP pressure limit Pupper thatmay be set to a prescribed maximum treatment pressure Pmax. In oneimplementation, the predetermined pressure increment ΔP and maximumtreatment pressure Pmax are 1 cm H₂O and 25 cm H₂O respectively. Inother implementations, the pressure increment ΔP can be as low as 0.1 cmH₂O and as high as 3 cm H₂O, or as low as 0.5 cm H₂O and as high as 2 cmH₂O. In other implementations, the maximum treatment pressure Pmax canbe as low as 15 cm H₂O and as high as 35 cm H₂O, or as low as 20 cm H₂Oand as high as 30 cm H₂O. The method 4500 then returns to step 4520.

At step 4560, the processor 4230 decreases the base pressure P₀ by adecrement, such that the resulting treatment pressure Pt is no lowerthan a lower APAP pressure limit Plower that may be set to a prescribedminimum therapeutic pressure Pmin. The method 4500 then returns to step4520. In one implementation, the decrement is proportional to the valueof Pt−Pmin, so that the decrease of Pt to the minimum therapeuticpressure Pmin in the absence of any detected events is exponential. Inone implementation, the constant of proportionality is set such that thetime constant τ of the exponential decrease of Pt is 60 minutes, and theminimum therapeutic pressure Pmin is 4 cm H₂O. In other implementations,the time constant τ could be as low as 1 minute and as high as 300minutes, or as low as 5 minutes and as high as 180 minutes. In otherimplementations, the minimum therapeutic pressure Pmin can be as low as0 cm H₂O and as high as 8 cm H₂O, or as low as 2 cm H₂O and as high as 6cm H₂O. Alternatively, the decrement in the base pressure P₀ could bepredetermined, so the decrease in Pt to the minimum therapeutic pressurePmin in the absence of any detected events is linear.

In one form of the present technology, the predetermined pressureincrement ΔP is smaller, and the time constant τ is longer, than inprevious implementations of the algorithm 4328. These differences,combined with the fact that the measures of flow limitation, apnea,hypopnea, patency, and snore are assessed on a single breath rather thanover multiple breaths, combine to give the control loop implemented bymethod 4500 in this form of the present technology a smoother, less“aggressive” character than previous implementations of the algorithm4328.

8.4.3.2.9 Initial Phase of Operation

The above described therapy modes are designed to be delivered to asleeping patient 1000. However, if the patient 1000 is the partyinitiating therapy, the patient 1000 is generally awake. If the PAPdevice 4000 begins to deliver therapeutic pressures as described aboveas soon as the patient 1000 initiates treatment (such as when thepatient first goes to bed at night or returns to therapy after a breakin sleep in middle of the night), the patient 1000 may find that thetreatment pressure Pt, even if initialised to the minimum therapeuticpressure Pmin, may be too high for them to fall asleep, or the rate ofincrease of pressure may be too high for the patient to comfortably fallasleep, so a purpose of therapy may be defeated.

Consequently there is a need for a “pre-sleep mode” of operation of thePAP device 4000 that may be implemented with one or more processors,such as the central controller or processor 4230. The pre-sleep mode canbe invoked when the patient 1000 initiates treatment and ends at asuitable time, such as when the patient 1000 is deemed by the PAP device4000 to have fallen asleep, and/or after a predetermined time limit haselapsed. A purpose of the pre-sleep mode of operation is to allow thepatient 1000 to fall asleep with low or more comfortable pressure(s),since therapy is not required while the patient 1000 is awake.Additionally, or alternatively, the pre-sleep mode may graduallyincrease a pressure provided to the patient, in order to improve thechance that the patient would be comfortable with the treatment. Thedelivered pressure during the pre-sleep mode may be sub-therapeutic, andmay follow a pre-sleep profile of pressure vs time, starting at apre-sleep pressure Ps that may be lower or even substantially lower thanthe minimum therapeutic pressure Pmin. The pre-sleep profile is chosento be compatible with the patient falling asleep. The delivered pressuremay therefore start at pre-sleep pressure Ps, which may be in the range2 to 6 cm H₂O, or 3 to 5 cm H₂O, preferably at or around 4 cm H₂O. Thepressure may then gradually increase, such as by a ramp (e.g.,continuous increase or gradual stepping of pressure) over a particularperiod of time toward the treatment pressure Pt, such as to the minimumtherapeutic pressure, Pmin, such as 10 cm H₂O or more or less or otherprescribed/titrated therapeutic treatment pressure that may besufficient to prevent events of sleep disordered breathing. Thisparticular time period over which the pressure changes from thepre-sleep pressure Ps to the predetermined minimum therapeutic pressureor other prescribed/titrated therapeutic treatment pressure as discussedherein may be considered a “ramp time”. As described in more detailherein, the ramp time may be an adapted or dynamic parameter that may bedetermined by any of the methodologies described in more detail herein.After the pre-sleep mode has ended (i.e., at the end of the ramp time),the PAP device 4000 may transition into a therapy mode, such a modewhere therapeutic pressure is fixed (e.g., a fixed CPAP or a fixedBi-level pressure treatment) or adjusted (e.g., automatically titratedin response to detected events of sleep disordered breathing). In someimplementations, the transition from pre-sleep mode to therapy mode mayinclude a period of time wherein pressure is further increased to reacha predetermined therapeutic pressure, such as by implementation of abridging period as disclosed in PCT Application No. PCT/AU2014/000208 toResMed Limited, titled “Method and apparatus for treatment ofrespiratory disorders,” the entire disclosure of which is incorporatedherein by reference. Where the words ‘ramp’ or ‘ramp time’ are used, itwill be understood that such references are used to generally refer toincreases in pressure or the length of time of said increase in thepre-sleep mode. For example, a ramp may comprise a series ofdiscontinuous pressure increases, as shown in FIG. 4H.

FIG. 4f is a state diagram illustrating an initial phase of operation4600 of the therapy engine module 4320 in one form of the presenttechnology. According to the initial phase of operation 4600, the PAPdevice 4000 enters the pre-sleep mode 4610 when the patient 1000initiates treatment. In one implementation, an initiation signal isgenerated, namely a Treatment-On signal input to the PAP device 4000 bythe patient 1000 via the input devices 4220. In another implementation,the initiation signal is a SmartStart signal generated by the processor4230 in response to detection by the ventilation determination algorithm4323 that the patient 1000 has started wearing the patient interface3000, and/or is breathing. Such detection may be made by the processor4230 in conventional fashion, for example as disclosed in Europeanpatent application no. EP 661071 to ResMed Limited, titled “Device forContinuous Positive Airway Pressure Breathing (CPAP)”. During thepre-sleep mode 4610, the processor 4230 initialises the deliveredpressure to the pre-sleep pressure Ps. The processor 4230 then controlsthe delivered pressure according to the pre-sleep profile.

The timing of the pre-sleep pressure profile during the pre-sleep modeis significant not only in allowing lower pressure to promote sleeponset but also in ensuring that sufficient therapeutic pressure topreserve sleep is delivered during sleep such as at sleep onset.Reaching the predetermined minimum therapeutic pressure too quickly maycause discomfort to the patient and prevent the patient from fallingasleep. Reaching the predetermined minimum therapeutic pressure and/ortransitioning to therapy mode too late may cause disruption to thepatient's sleep due to untreated events of the patient's respiratorydisorder(s).

Therefore, the PAP device 4000 may be configured to transition from thepre-sleep mode 4610 to therapy mode 4630 when a timer reaches apre-sleep limit 4620. The pre-sleep limit therefore is functionally theramp time. The pre-sleep limit may be, or may be a function of, apre-sleep or sleep onset parameter(s), such as a function of one or moreamounts of time(s) for sleep onset to occur, where such pre-sleep orsleep onset parameters may be historical in the sense that they are not,at least in part, from information regarding a current treatment sessionbut may be from previously treatment or sleep sessions by the particularuser. The pre-sleep limit may be set based on the pre-sleep parameter.Pre-sleep parameters may include sleep onset time or other similarparameter indicative of time(s) that it takes a person to transition tosleep from wakefulness, such as from previous/historical treatmentsessions. Such parameters may optionally be derived/detected by sensorsof a device (e.g., flow sensor, electrocardiogram, electroencephalogram,and/or motion sensor, etc.) such as to determine a measure of time ofsleep onset. A sleep onset time may be the length of time from when apatient gets into bed, or when pressure treatment device is activated,to a time when initial sleep occurs.

To automatically determine the pre-sleep limit, one or more processorsmay collect information regarding the pre-sleep parameters of a patient,such as sleep onset times. In some implementations, the processor 4230of the PAP device 4000 may measure sleep onset times as the length oftime between when the PAP device starts providing pressure to thepatient to when sleep onset is detected. Sleep onset may be detectedusing the PAP device 4000. For example, sleep onset may bedetected/measured by any of the methods described in PCT/AU2010/000894,the entire disclosure of which is incorporated herein by reference. Byway of further example, such as during the pre-sleep mode 4610, theprocessor 4230 of the PAP device 4000 may monitor the respiratory flowQr or other sensor signal to detect sleep onset. Sleep onset may bedetected by any conventional method of real-time sleep statedetermination such as by detection and analysis of biometric parameterssuch as respiratory and/or cardia parameters. In one implementation,sleep onset is detected if one or both of the following conditionsoccur:

-   -   Multiple occurrences of SDB events, such as flow limitation,        apnea, hypopnea, or snore, as determined from the measures of        these quantities obtained as described above, within a first        predetermined interval. For example, three or more obstructive        apnea or hypopnea events within a two minute interval; or five        instances of snore within a 5-breath interval.    -   Few or no respiratory disturbances for a second predetermined        interval. The second predetermined interval may be in the range        10 to 50 breaths, or 20 to 40 breaths, or 25 to 35 breaths, or        from 1 to 10 minutes, 1 to 5 minutes, or 2, 3, 4, 5, 6, 7, 8 or        9 minutes, or some other time limit. To detect no respiratory        disturbances, the processor 4230 tests for lack of variation        over the second predetermined interval of one or more of the        following respiratory variables:        -   Tidal volume;        -   Inspiratory time;        -   Respiratory rate;        -   Inspiratory peak flow;        -   Expiratory peak flow location;        -   Time since last breath.

Additionally or alternatively, pre-sleep parameters, such as sleep onsettimes, may be input to the device by a user. Such input may be requestedor prompted, such as by a user interface, by the one or more processors,such as processor 4230, and received at the one or more input devices4220 of the PAP device 4000. Measured and/or received sleep onset timesmay be stored in a memory, such as memory 4260.

The pre-sleep limit 4620 may then be determined as a function of thecollected (e.g., detected/measured and/or input) information for thepatient. For example, the pre-sleep limit 4620 may be calculated by thePAP device such as by setting the pre-sleep limit based on a maximum, amean, or a percentile of the collected sleep onset times. The particularfunction by which the pre-sleep limit is determined/calculated by thePAP device may be pre-set (e.g., a default or fixed function) on the PAPdevice or may be selected by a user and/or clinician. As an example,over the course of 20 days, 20 measured sleep onset times may becollected, as shown in Table 1 below:

TABLE 1 Measured sleep Day onset time (min) 1 15 2 16 3 16 4 20 5 24 618 7 19 8 18 9 17 10 16 11 10 12 15 13 14 14 17 15 12 16 13 17 14 18 1519 18 20 19

Although the illustrative time values shown here are in minutes, it willbe understood that other time units may serve as the pre-sleep limit,such as number of hours, number of seconds, number of detected breaths,etc.

For the collected values in Table 1, if using a maximum of the collectedsleep onset times as the pre-sleep limit, the pre-sleep limit iscalculated by the device and set to be 24 minutes. If using a mean ofthe collected sleep onset times as the pre-sleep limit, the pre-sleeplimit is calculated by the device and set to be 16.3 minutes. If using a90^(th) percentile of the collected sleep onset times as the pre-sleeplimit, the pre-sleep limit is calculated by the device and set to be 20minutes.

In some versions, the pre-sleep limit may alternatively be a furtherfunction of the determined percentile time, such as 150%, 125%, 100% or90% of the 70^(th), 80^(th), 90^(th) or 100^(th) (i.e. maximum)percentile time. For the collected values in Table 1, if the pre-sleeplimit is set as 125% of the 90^(th) percentile time, the pre-sleep limitis calculated by the device to be 25. As new information is collected,the time limit may be updated dynamically or at discrete intervalsindicated by a user or by the device so as to permit an adaptation to apatient's sleeping pattern. Alternatively, the pre-sleep limit may beset to the most recent single collected sleep onset time (e.g., onedetermined from the previous treatment session).

In some implementations, the pre-sleep limit may be based on informationthat is collected within a timeframe, or window of time. The pre-sleeplimit may be determined dynamically based on the timeframe, which may bea rolling window/timeframe, for example based on previous 5, 10 or 15days of sleep data. Thus, in such an example, the device may collectdata during a number of treatment sessions (e.g., days) of theparticular time window and then set the pre-sleep limit for the nexttreatment session at the conclusion of the time window. Such a timewindow length may be a selectable parameter input to the device by auser such as by a user selecting the number of days/treatment sessionsin a user interface of the device. In the case of a rollingtimeframe/window, on each subsequent day/treatment session the precedingsleep onset times of the window are used (e.g., by use of a last in,first out buffer of sleep onset times with a buffer length equal to thewindow). In some cases, the pre-sleep limit may be calculated from thepreceding timeframe/window and only be recalculated and the conclusionof re-collection of the full window such as by resetting the pre-sleeplimit once every five days in the case of a five day window, etc.

For example, a pre-sleep limit set based on sleep onset times collectedin a previous 10 day window, for example, may collect the first 10 sleeponset times in Table 1. As such, on day 11, if the pre-sleep limit isdetermined as a maximum of the collected sleep onset times in thetimeframe, the pre-sleep limit is calculated by the device and set to be24 minutes. In the case of the rolling window, on day 16, the timeframeused to determine the pre-sleep limit is shifted from day 6 to day 15 sothat the pre-sleep limit is set to 19 minutes, which is the maximum forthe updated timeframe.

Optionally, the time limit of the window may be calibrated, such asbased on the user input. In this regard, a user's selection of such acalibration event would reset the sleep information associated with thewindow so that the window would then begin collecting the sleepinformation for the window time frame (e.g., 5, 10 or 15 days/treatmentsessions etc.).

When the device is unable to calculate a pre-sleep limit due to theabsence or insufficient amount of collected sleep onset time, such asfor new device or a new patient, a default pre-sleep limit may be set onthe PAP device. The default pre-sleep limit may be, for example, set orchosen by a user or may be a factory setting. In other implementations,the default pre-sleep limit may be based on an average sleep onset timefor a person in the patient's demographic.

In some implementations, the one or more processors, such as of the PAPdevice, may provide for display a prompt to a user with potentialpre-sleep parameters for selection. As such, the user can view datarelated to, for example, measured lengths of time taken for the patientto go to sleep from previously sessions, and then select the pre-sleeplimit. The data displayed for the user may include one or more collectedsleep onset times and/or one or more statistics of the collected sleeponset times. For example, based on the collected sleep onset times inTable 1, the prompt provided to the user may display a message asfollows: “It looks like you are typically (90% of the time) fallingasleep within 20 minutes of operation. Would you like to set your ramptime to 20 minutes?” In other implementations, a plurality of optionsmay be presented on the display based on different functions(percentiles, means, etc.) of the collected information for the sleeponset times as previously described, and a user may then select anoption from the plurality.

Once the pre-sleep limit is determined or selected, the one or moreprocessors may determine a pre-sleep pressure profile that starts at apre-sleep pressure Ps and ramps up to another pressure (e.g., apredetermined minimum therapeutic pressure Pmin) over the particularlydetermined/chose pre-sleep limit. The slope and/or shape of thepre-sleep profile may be determined by any conventional method known inthe art. Any slope and/or shape for ramping known in the art, such asthose described in PCT Application No. PCT/AU2014/000208, may beutilized by the processor 4230 of the PAP device 4000 to controlpressure according to the pre-sleep profile during the pre-sleep limit.

The PAP device 4000 may deliver pressure to the patient according to thedetermined pre-sleep pressure profile.

FIGS. 4G and 4H depict graphs illustrating examples of the initial phaseof operation 4600 of the therapy engine module 4320 of FIG. 4D asdescribed above with reference to FIG. 4F such as in accordance with apre-sleep limit.

In this example shown in FIG. 4G, the pre-sleep limit 4620 is determinedto be 21 minutes. The solid line trace 4700 represents the deliveredpressure over time, such as by ramping sub-therapeutic pressures towardtreatment or therapeutic pressures over a time span representative ofthe pre-sleep limit. The trace 4700 during the pre-sleep mode 4610follows a pre-sleep profile 4710, which is determined by the processor4230 to run over the course of the pre-sleep limit 4620 of 21 minutes.The pre-sleep profile 4710 optionally comprises one increase or a seriesof linear increases of slope equal to 1 cm H₂O per minute and durationone minute, interleaved with optional pause periods of three minutesduring which the delivered pressure is constant. The slope and durationof the linear increases and the duration of the pause periods are chosensuch that the delivered pressure would start at pre-sleep pressure Ps, 4cm H₂O in this example, and reach the minimum therapeutic pressure Pmin,10 cm H₂O in this example, at the pre-sleep limit time parameter of 21minutes.

Additionally or alternatively, when sleep onset is detected prior tocompletion of the pre-sleep profile and during a current session withthe treatment device (i.e., not an historic sleep onset for thepatient), a new profile may optionally be determined for ramping thepressure from what it is when sleep onset is presently detected, to theminimum therapeutic pressure Pmin, or other treatment pressure. In someimplementations, the new profile takes a shorter amount of time than thepre-sleep profile to reach the minimum therapeutic pressure Pmin so thatthe PAP device 4000 may start operating in therapy mode 4630 earlierthan the time projected by the pre-sleep profile.

In the example shown in FIG. 4H, the pre-sleep limit is determined to be21 minutes like the example in FIG. 4G, and the same pre-sleep profileis determined for implementation on the PAP device. In FIG. 4H, currentsleep onset is detected at 14 minutes, as indicated by circle 4750, atwhich time a new profile 4810 that is non-historic is determined. Thetrace 4700 follows the new profile 4810 comprising a series of linearincreases of slope equal to 1 cm H₂O per minute and duration one minute,interleaved with pause periods of one minute during which the deliveredpressure is constant. The slope and duration of the linear increases arethe same as those of the pre-sleep profile, i.e., 1 cm H₂O per minuteand one minute. The duration of the pause periods is chosen to be oneminute such that the delivered pressure reaches the minimum therapeuticpressure Pmin at the a further time parameter such as three minutes. Assuch, the minimum therapeutic pressure Pmin is reached in 17 minutes inFIG. 4H rather the determined pre-sleep limit, 21 minutes.

The features described above of the initial phase operation provide asystem that can be configured to customize ramp time to a particularpatient. Because the system may be configured to detect sleep onsettime, unreliability with self-reporting sleep onset times might bediminished. The dynamic nature of determining the pre-sleep limit allowsfor adaptation to changing sleep habits of a patient, and may minimizethe effect of unreliable sleep state detection. With a customized ramptime, the system may initiate and ramp up to administer treatment in away that more suits the particular patient. As such, there may be lesslikelihood of disturbing or discomforting a patient as they are fallingasleep or when they are sleeping, and patients may be more likely to usethe system and comply with therapy.

In some cases, as previously described, sleep information (e.g., currentand/or historic sleep onset parameters) is detected by a PAP device,such as with an analysis of information from a flow and/or pressuresignals generated by a flow sensor and/or pressure sensor of the PAPdevice. For example, sleep onset may be detected by any of the methodsdescribed in PCT/AU2010/000894, the entire disclosure of which isincorporated herein by reference. However, in some versions, sleepinformation (e.g., historic sleep onset parameters) may be detected byother apparatus, and communicated to the PAP apparatus for setting ofthe sleep related pressure ramp of the pressure therapy apparatus. Forexample, an RF motion sensor, such as the ResMed Sensor TechnologiesLimited's SleepMinder sensor, may be implemented to detect andcommunicate sleep information, such as sleep onset or sleep onsettime(s), to the PAP device for setting of the pressure ramp. Such a RFmotion sensor may be, for example, any motion sensor described inPCT/EP2016/069413, PCT/US2013/051250 and/or PCT/US2014/045814, theentire disclosures of which are incorporated herein by reference.

8.5 Humidifier 5000

In one form of the present technology there is provided a humidifier5000 comprising a water reservoir and a heating plate (not shown).

8.6 Glossary

For the purposes of the present technology disclosure, in certain formsof the present technology, one or more of the following definitions mayapply. In other forms of the present technology, alternative definitionsmay apply.

8.6.1 General

Air: In certain forms of the present technology, air may be taken tomean atmospheric air, and in other forms of the present technology airmay be taken to mean some other combination of breathable gases, e.g.atmospheric air enriched with oxygen.

Positive Airway Pressure (PAP) Therapy: The application of a supply ofair to the entrance to the airways at a pressure that is continuouslypositive with respect to atmosphere.

Positive Airway Pressure (PAP) device: A device for providing positiveairway pressure therapy.

Continuous Positive Airway Pressure (CPAP) therapy: Positive airwaypressure therapy in which the treatment pressure is approximatelyconstant through a respiratory cycle of a patient. In some forms, thepressure at the entrance to the airways will vary by a few centimetresof water within a single respiratory cycle, for example being higherduring inhalation and lower during exhalation. In some forms, thepressure at the entrance to the airways will be slightly higher duringexhalation, and slightly lower during inhalation.

Automatic Positive Airway Pressure (APAP) therapy: CPAP therapy in whichthe treatment pressure is continually adjustable between minimum andmaximum limits, depending on the presence or absence of indications ofSDB events.

8.6.2 Aspects of PAP Devices

Air circuit: A conduit or tube constructed and arranged in use todeliver a supply of air between a PAP device and a patient interface. Inparticular, the air circuit may be in fluid connection with the outletof the pneumatic block and the patient interface. The air circuit may bereferred to as air delivery tube. In some cases there may be separatelimbs of the circuit for inhalation and exhalation. In other cases asingle limb is used.

Blower: A device that delivers a flow of air at a pressure above ambientpressure.

Controller: A device or portion of a device that adjusts an output basedon an input. For example one form of controller has a variable that isunder control—the control variable—that constitutes the input to thedevice, and a set point for the variable. The output of the device is afunction of the current value of the control variable and the set point.

Transducers: A device for converting one form of energy or signal intoanother. A transducer may be a sensor or detector for convertingmechanical energy (such as movement) into an electrical signal. Examplesof transducers include pressure sensors, flow sensors, carbon dioxide(CO₂) sensors, oxygen (O₂) sensors, effort sensors, movement sensors,noise sensors, a plethysmograph, and cameras.

8.6.3 Aspects of the Respiratory Cycle

Apnea: Preferably, apnea will be said to have occurred when flow fallsbelow a predetermined threshold for a duration, e.g. 10 second. Anobstructive apnea will be said to have occurred when, despite patienteffort, some obstruction of the airway does not allow air to flow. Acentral apnea will be said to have occurred when an apnea is detectedthat is due to a reduction in breathing effort, or the absence ofbreathing effort.

Breathing rate: The rate of spontaneous respiration of a patient,usually measured in breaths per minute.

Duty cycle: The ratio of inhalation time, Ti to total breath time, Ttot.

Effort (breathing): Preferably breathing effort will be said to be thework done by a spontaneously breathing person attempting to breathe.

Expiratory portion of a breathing cycle: The period from the start ofexpiratory flow to the start of inspiratory flow.

Flow limitation: Preferably, flow limitation will be taken to be thestate of affairs in a patient's respiration where an increase in effortby the patient does not give rise to a corresponding increase in flow.Where flow limitation occurs during an inspiratory portion of thebreathing cycle it may be described as inspiratory flow limitation.Where flow limitation occurs during an expiratory portion of thebreathing cycle it may be described as expiratory flow limitation.

Hypopnea: Preferably, a hypopnea will be taken to be a reduction inflow, but not a cessation of flow. In one form, a hypopnea may be saidto have occurred when there is a reduction in flow below a threshold fora duration. In one form in adults, the following either of the followingmay be regarded as being hypopneas:

-   -   (i) a 30% reduction in patient breathing for at least 10 second        plus an associated 4% desaturation; or    -   (ii) a reduction in patient breathing (but less than 50%) for at        least 10 second, with an associated desaturation of at least 3%        or an arousal.

Inspiratory portion of a breathing cycle: Preferably the period from thestart of inspiratory flow to the start of expiratory flow will be takento be the inspiratory portion of a breathing cycle.

Patency (airway): The degree of the airway being open, or the extent towhich the airway is open. A patent airway is open. Airway patency may bequantified, for example with a value of one (1) being patent, and avalue of zero (0), being closed.

Positive End-Expiratory Pressure (PEEP): The pressure above atmospherein the lungs that exists at the end of expiration.

Peak flow (Qpeak): The maximum value of flow during the inspiratoryportion of the respiratory flow waveform.

Respiratory flow, airflow, patient airflow, respiratory airflow (Qr):These synonymous terms may be understood to refer to the PAP device'sestimate of respiratory airflow, as opposed to “true respiratory flow”or “true respiratory airflow”, which is the actual respiratory flowexperienced by the patient, usually expressed in litres per minute.

Tidal volume (Vt): The volume of air inhaled or exhaled during normalbreathing, when extra effort is not applied.

(inhalation) Time (Ti): The duration of the inspiratory portion of therespiratory flow waveform.

(exhalation) Time (Te): The duration of the expiratory portion of therespiratory flow waveform.

(total) Time (Ttot): The total duration between the start of theinspiratory portion of one respiratory flow waveform and the start ofthe inspiratory portion of the following respiratory flow waveform.

Typical recent ventilation: The value of ventilation around which recentvalues over some predetermined timescale tend to cluster, that is, ameasure of the central tendency of the recent values of ventilation.

Upper airway obstruction (UAO): includes both partial and total upperairway obstruction. This may be associated with a state of flowlimitation, in which the level of flow increases only slightly or mayeven decrease as the pressure difference across the upper airwayincreases (Starling resistor behaviour).

Ventilation (Vent): A measure of the total amount of gas being exchangedby the patient's respiratory system, including inspiratory and/orexpiratory flow, per unit time. When expressed as a volume per minute,this quantity is often referred to as “minute ventilation”. Minuteventilation is sometimes given simply as a volume, understood to be thevolume per minute.

8.6.4 PAP Device Parameters

Flow rate: The instantaneous volume (or mass) of air delivered per unittime. While flow rate and ventilation have the same dimensions of volumeor mass per unit time, flow rate is measured over a much shorter periodof time. Flow rate may be nominally positive for the inspiratory portionof a breathing cycle of a patient, and hence negative for the expiratoryportion of the breathing cycle of a patient. In some cases, a referenceto flow rate will be a reference to a scalar quantity, namely a quantityhaving magnitude only. In other cases, a reference to flow rate will bea reference to a vector quantity, namely a quantity having bothmagnitude and direction. Flow rate (sometimes referred to in shorthandas flow) will be given the symbol Q. Total flow, Qt, is the flow of airleaving the PAP device. Vent flow, Qv, is the flow of air leaving a ventto allow washout of exhaled gases. Leak flow, Ql, is the flow rate ofunintentional leak from a patient interface system. Respiratory flow,Qr, is the flow of air that is received into the patient's respiratorysystem.

Leak: Preferably, the word leak will be taken to be a flow of air to theambient. Leak may be intentional, for example to allow for the washoutof exhaled CO₂. Leak may be unintentional, for example, as the result ofan incomplete seal between a mask and a patient's face.

Pressure: Force per unit area. Pressure may be measured in a range ofunits, including cm H₂O, g-f/cm², hectopascal. 1 cm H₂O is equal to 1g-f/cm² and is approximately 0.98 hectopascal. In this specification,unless otherwise stated, pressure is given in units of cm H₂O. Thepressure in the patient interface is given the symbol Pm, while thetreatment pressure, which represents a target value to be achieved bythe mask pressure Pm at the current instant of time, is given the symbolPt.

8.6.5 Anatomy of the Respiratory System

Diaphragm: A sheet of muscle that extends across the bottom of the ribcage. The diaphragm separates the thoracic cavity, containing the heart,lungs and ribs, from the abdominal cavity. As the diaphragm contractsthe volume of the thoracic cavity increases and air is drawn into thelungs.

Larynx: The larynx, or voice box houses the vocal folds and connects theinferior part of the pharynx (hypopharynx) with the trachea.

Lungs: The organs of respiration in humans. The conducting zone of thelungs contains the trachea, the bronchi, the bronchioles, and theterminal bronchioles. The respiratory zone contains the respiratorybronchioles, the alveolar ducts, and the alveoli.

Nasal cavity: The nasal cavity (or nasal fossa) is a large air filledspace above and behind the nose in the middle of the face. The nasalcavity is divided in two by a vertical fin called the nasal septum. Onthe sides of the nasal cavity are three horizontal outgrowths callednasal conchae (singular “concha”) or turbinates. To the front of thenasal cavity is the nose, while the back blends, via the choanae, intothe nasopharynx.

Pharynx: The part of the throat situated immediately inferior to (below)the nasal cavity, and superior to the oesophagus and larynx. The pharynxis conventionally divided into three sections: the nasopharynx(epipharynx) (the nasal part of the pharynx), the oropharynx(mesopharynx) (the oral part of the pharynx), and the laryngopharynx(hypopharynx).

8.7 Other Remarks

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

Unless the context clearly dictates otherwise and where a range ofvalues is provided, it is understood that each intervening value, to thetenth of the unit of the lower limit, between the upper and lower limitof that range, and any other stated or intervening value in that statedrange is encompassed within the technology. The upper and lower limitsof these intervening ranges, which may be independently included in theintervening ranges, are also encompassed within the technology, subjectto any specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the technology.

Furthermore, where a value or values are stated herein as beingimplemented as part of the technology, it is understood that such valuesmay be approximated, unless otherwise stated, and such values may beutilized to any suitable significant digit to the extent that apractical technical implementation may permit or require it.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this technology belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present technology, a limitednumber of the exemplary methods and materials are described herein.

When a particular material is identified as being preferably used toconstruct a component, obvious alternative materials with similarproperties may be used as a substitute. Furthermore, unless specified tothe contrary, any and all components herein described are understood tobe capable of being manufactured and, as such, may be manufacturedtogether or separately.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include their plural equivalents,unless the context clearly dictates otherwise.

All publications mentioned herein are incorporated by reference todisclose and describe the methods and/or materials which are the subjectof those publications. The publications discussed herein are providedsolely for their disclosure prior to the filing date of the presentapplication. Nothing herein is to be construed as an admission that thepresent technology is not entitled to antedate such publication byvirtue of prior invention. Further, the dates of publication providedmay be different from the actual publication dates, which may need to beindependently confirmed.

Moreover, in interpreting the disclosure, all terms should beinterpreted in the broadest reasonable manner consistent with thecontext. In particular, the terms “comprises” and “comprising” should beinterpreted as referring to elements, components, or steps in anon-exclusive manner, indicating that the referenced elements,components, or steps may be present, or utilized, or combined with otherelements, components, or steps that are not expressly referenced.

The subject headings used in the detailed description are included onlyfor the ease of reference of the reader and should not be used to limitthe subject matter found throughout the disclosure or the claims. Thesubject headings should not be used in construing the scope of theclaims or the claim limitations.

Although the technology herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thetechnology. In some instances, the terminology and symbols may implyspecific details that are not required to practice the technology. Forexample, although the terms “first” and “second” may be used, unlessotherwise specified, they are not intended to indicate any order but maybe utilised to distinguish between distinct elements. Furthermore,although process steps in the methodologies may be described orillustrated in an order, such an ordering is not required. Those skilledin the art will recognize that such ordering may be modified and/oraspects thereof may be conducted concurrently or even synchronously.

It is therefore to be understood that numerous modifications may be madeto the illustrative embodiments and that other arrangements may bedevised without departing from the spirit and scope of the technology.

REFERENCE LABEL LIST Patient 1000 patient interface 3000 seal-formingstructure 3100 plenum chamber 3200 positioning and stabilising structure3300 Vent 3400 connection port 3600 PAP device 4000 external housing4010 upper portion 4012 Portion 4014 Panel 4015 Chassis 4016 Handle 4018pneumatic block 4020 pneumatic component 4100 air filter 4110 inlet airfilter 4112 outlet air filter 4114 Muffler 4120 inlet muffler 4122outlet muffler 4124 pressure device 4140 Blower 4142 brushless DC motor4144 anti-spill back valve 4160 air circuit 4170 supplemental oxygen4180 electrical component 4200 PCBA 4202 power supply 4210 input device4220 central controller/processor 4230 Clock 4232 therapy devicecontroller 4240 protection circuit 4250 Memory 4260 Transducer 4270pressure transducer 4272 flow transducer 4274 motor speed transducer4276 data communication interface 4280 remote external communicationnetwork 4282 local external communication network 4284 such remoteexternal device 4286 local external device 4288 output device 4290display driver 4292 Display 4294 Algorithm 4300 pre-processing module4310 pressure compensation algorithm 4312 vent flow algorithm 4314 leakflow algorithm 4316 respiratory flow algorithm 4318 therapy enginemodule 4320 phase determination algorithm 4321 waveform determinationalgorithm 4322 ventilation determination algorithm 4323 inspiratory flowlimitation determination algorithm 4324 apnea/hypopnea determinationalgorithm 4325 snore determination algorithm 4326 airway patencydetermination algorithm 4327 therapy parameter determination algorithm4328 control module 4330 fault condition module 4340 Method 4500 Step4520 Step 4530 Step 4540 Step 4550 Step 4560 initial phase of operation4600 pre-sleep mode 4610 pre-sleep limit 4620 therapy mode 4630 trace4700 pre-sleep profile 4710 time 4750 new profile 4810 Humidifier 5000heater 5240 humidity controller 5250

The invention claimed is:
 1. An apparatus for treating a respiratorydisorder comprising: a breathable gas pressure generating device, and acontroller, including at least one processor, the controller configuredto: collect historic sleep onset parameters concerning timing of apatient falling asleep; determine, based on the historic sleep onsetparameters, a pre-sleep limit as a function of a percentage of a valueof a percentile of a plurality of the historic sleep onset parameters;determine a pre-sleep profile of pressure versus time having a durationspanning the pre-sleep limit and having a plurality of rampingsub-therapeutic pressures; and control, upon initiation of treatment,setting of the breathable gas pressure generating device according tothe pre-sleep profile of pressure versus time.
 2. The apparatusaccording to claim 1, wherein the controller is configured to collectthe historic sleep onset parameters by: detecting, with one or moresensors, sleep onset of the patient during use of the breathable gaspressure generating device; and determining a length of time for thesleep onset of the patient.
 3. The apparatus according to claim 1,wherein the controller is configured to collect the historic sleep onsetparameters by receiving a sleep onset time at a user input device. 4.The apparatus according to claim 1, the controller is configured tocollect the plurality of the historic sleep onset parameters accordingto a window timeframe comprising a number of treatment sessions.
 5. Theapparatus according to claim 4, wherein the window timeframe is arolling window timeframe.
 6. The apparatus according to claim 1, whereinthe controller is further configured to set a default pre-sleep limit inan absence of a collection of the historic sleep onset parameters. 7.The apparatus according to claim 1, wherein the controller is furtherconfigured to: control a display to provide a prompt for input, theprompt for input including: one or both of (a) at least one of thehistoric sleep onset parameters, and (b) at least one statisticconcerning the historic sleep onset parameters; and determine thepre-sleep limit based on input received in response to the prompt. 8.The apparatus according to claim 1, wherein the pre-sleep profile startsdelivered pressure at a first pressure and ends at a minimum therapeuticpressure, the minimum therapeutic pressure being higher than the firstpressure.
 9. A method for controlling a pressure treatment for arespiratory disorder comprising: generating a flow of breathable gas ata pressure above atmospheric pressure with a pressure generating device,and in one or more controllers: collecting historic sleep onsetparameters concerning timing of a patient falling asleep; determining,based on the historic sleep onset parameters, a pre-sleep limit as afunction of a percentage of a value of a percentile of a plurality ofthe historic sleep onset parameters; determining a pre-sleep profile ofpressure versus time having a duration spanning the pre-sleep limit andhaving a plurality of ramping sub-therapeutic pressures; andcontrolling, upon initiation of treatment, setting of the flow ofbreathable gas according to the pre-sleep profile of pressure versustime.
 10. The method according to claim 9, further comprising in the oneor more controllers, collecting the historic sleep onset parameters by:detecting, with one or more sensors, sleep onset of the patient duringuse of the pressure generating device; and determining a length of timefor the sleep onset of the patient.
 11. The method according to claim 9,wherein the collecting the historic sleep onset parameters comprisesreceiving a sleep onset time at a user input device.
 12. The methodaccording to claim 9, further comprising, in the one or morecontrollers, collecting the plurality of the historic sleep onsetparameters according to a window timeframe comprising a number oftreatment sessions.
 13. The method according to claim 12, wherein thewindow timeframe is a rolling window timeframe.
 14. The method accordingto claim 9, further comprising, in the one or more controllers, settinga default pre-sleep limit in an absence of a collection of the historicsleep onset parameters.
 15. The method according to claim 9, furthercomprising, in the one or more controllers: controlling a display toprovide a prompt for input, the prompt for input including: one or bothof (a) at least one of the historic sleep onset parameters, and (b) atleast one statistic concerning the historic sleep onset parameters; anddetermining the pre-sleep limit based on input received in response tothe prompt.
 16. The method according to claim 9, wherein the pre-sleepprofile starts delivered pressure at a first pressure and ends at aminimum therapeutic pressure, the minimum therapeutic pressure beinghigher than the first pressure.